Tainted: The Problem With Pot and Pesticides

Should you worry about inhaling pesticide residues on the cannabis you’re smoking? Find out how to source a safe supply of eco-friendly weed.

Old-time heads will remember the Great Paraquat Pot Scare of the late 1970s, when Mexico, as part of a US-government-backed cannabis-eradication campaign, sprayed the potent herbicide onto fields of weed destined for export to the United States. While a 1995 study found that “no lung or other injury in cannabis users has ever been attributed to paraquat contamination,” other research linked exposure to an increased risk of developing Parkinson’s disease.

At the time, fear about the effects of inhaling paraquat-contaminated pot motivated back-to-the-land hippies to breed their own unique hybridized strains, and in time homegrown California cannabis largely replaced smuggled bales from south of the border in the popular consciousness. Even today, most cannabis consumers wistfully imagine that their buds hail from some wholly unspoiled remote hillside in Humboldt County. Unfortunately, that bucolic picture is far from the reality.

Anyone who smokes cannabis, black-market or otherwise, is unwittingly participating in a huge uncontrolled experiment involving millions of human subjects. Most pot deals in prohibition states are a “take it or leave it” proposition involving a scarce commodity; people buy whatever’s being offered, and possible pesticide contamination isn’t on their radar. Even in states with a robust medical marijuana market, lack of official oversight creates financial incentives that sometimes trump concern for public health and safety. This leads some growers to harvest their plants by any means necessary, including through the use of some truly scary rodenticides, fungicides and pesticides—none of which have been scientifically studied to determine their effects on human health when combusted and inhaled.

And so, after legalizing cannabis and implementing regulatory oversight, states like Colorado, Washington and Oregon have discovered a disturbing problem: An alarming percentage of cannabis is tainted by high levels of pesticide residue, prompting recalls and public-safety alerts. Chemicals like myclobutanil, imidacloprid, abamectin, etoxazole and spiromesifen, which are found in popular pest-control products, have been detected as residue on cannabis flowers and concentrated further in extracts and edibles.

Colorado’s TruCannabis recalled flowers in October 2015 due to pesticide contamination; tainted trim from that incident was traced to batches of Edipure products and required the removal of some 20,000 packages from dispensary shelves. In the same month, in the first product-liability lawsuit of its kind, medical patients Brandan Flores and Brandie Larrabee sued LivWell, a Colorado producer operating some of the largest grow operations in the world, over its alleged use of Eagle 20.

“I want these companies to take a step back and look at what they are putting into their products,” said Flores, 24, speaking to the Los Angeles Times. “These warehouses are getting big and really sloppy. They’re adding chemicals to make things more efficient and more potent. But there are so many chemicals now that you might as well get prescription medication.”

On November 3, 2016, Oregon officials issued a second public-health alert for specific batches of cannabis. About 370 customers had purchased the strains Dutch Treat, Pleeze and Dryzl from three different dispensaries in North Bend, Salem and Eugene that contained high levels of either spinosad or piperonyl butoxide. The alert prompted the heads of the Oregon Health Authority, Liquor Control Commission and Department of Agriculture to write a letter warning growers that they may be violating state regulations by using pesticides not permitted under the state’s Pesticide Control Act, and that the Department of Agriculture would investigate those whose products failed pesticide screenings.

California’s situation may be even worse than a few isolated incidents, with Steep Hill Labs reporting that 85 percent of the samples submitted for inspection contained levels of pesticide residue prohibited by Oregon standards. According to Dr. Donald Land, a professor of chemistry, forensic science and biotechnology at the University of California, Davis, and an analytical chemist with decades of experience who has been working with Steep Hill, the problem is bigger than many can even imagine.

“There’s really no data,” he says when asked if these pesticides are safe to inhale. “Nobody knows for sure, but the difference between eating something and inhaling something directly into the lungs is huge.”

Animal testing as part of rigorous, expensive studies is usually how pesticide products are certified by the Environmental Protection Agency as being reasonably safe for human consumption. Because of the federally illegal status of cannabis, no such certifications can be obtained for pesticides used on the herb, especially because the health effects of combusting and inhaling pesticides rather than ingesting them are different and unknown.

Cannabis buds can get contaminated in a few different ways, including the direct application of pesticides on flowering plants; drift from neighboring fields of food crops; or (particularly insidiously) through systemic contamination. “Some pesticides stay on the outside of the plant and don’t go internal, so as rain washes it off, it degrades and goes away after a period of time,” Dr. Land explains. “Mycobutanil can get into the internal fluids of the plant, and we know from studies on other plants that it can stay in plant tissues for years.”

Dr. Land suspects that this systemic contamination could be why cannabis samples fail pesticide screenings even when the cannabis is grown organically by producers determined to do the right thing. “A number of cultivators tell us that they’ve never used pesticides on their plants whatsoever, and yet we have unmistakable traces of these pesticides on those same plants,” Dr. Land continues. “We suspect that the clones or even the mother plants may be contributing [to this].”

Even if a mother plant is treated with pesticides, the perception is that the clones will be just fine. But that’s not necessarily true: If the pesticide used causes systemic contamination, it could enter the whole plant and persist for years, meaning that clones taken from the same plant would have presumably small but significant concentrations of pesticide as well. Clone producers preventatively treat their clones with pesticides numerous times between cutting and sale, so it’s important to grow from seed if you’re seeking to eliminate any potential contamination.

And your dabs, waxes and shatters aren’t immune from contamination either—in fact, extraction processes may “concentrate certain pesticides even more so than cannabinoids,” Dr. Land says, noting that most extraction processes get rid of microorganisms but not chemical contaminants. As a result, Steep Hill invested in expensive technology to test for pesticides at very low levels in order to predict if a flower sample will result in a highly contaminated concentrate.

Don’t Panic (if It’s Organic)

According to Dr. Land, the first line of defense is rigorously testing all cannabis products for pesticides and preventing the contaminated ones from reaching the market. He also believes that more research is needed to establish safe “action levels” for various pesticides and to determine where the contamination has originated, along with greater consumer education and awareness. “There needs to be a realization on the part of consumers that this is an issue, and that will drive the market,” Dr. Land says. “People need knowledge of exactly what they’re buying.”

Third-party certification agencies are a good start toward identifying safe suppliers and responsible growers, but consumers should investigate all such claims thoroughly. Also, since the word “organic” is a federally regulated term, it can’t be applied officially to cannabis crops. Dr. Land says the word “organic” doesn’t tell him anything when it comes to cannabis; he needs to know the standards used to verify that claim, including whether there’s been testing for pesticides.

Beyond the potential health risks to tokers, pesticide use has serious environmental consequences. “There are no pesticides registered specifically for use directly on marijuana and the use of pesticides on marijuana plants has not been reviewed for safety or human health effects,” reads a dispatch from the California State Water Board. Intending to reduce the environmental harms caused by clandestine grow ops in the remote Humboldt hills, the CSWB distributed a pamphlet titled “Know Before You Grow,” which educates growers in sensitive watersheds about improper pesticide use. Applying too many chemicals and using products irresponsibly causes toxic runoff into local rivers and streams, poisoning fish and wildlife. And the rodenticides left at outdoor marijuana grows threaten the endangered Pacific fisher, a rare predator belonging to the weasel family.

Conversely, growing cannabis indoors results in an enormous carbon footprint for each pound produced. The term “sun-grown” has emerged as a way to rebrand outdoor cannabis as a much more eco-friendly choice, but that term is also vague and has no meaning set by regulations.

Andrew Black, the founder of Certified Kind in Oregon, seeks to go “beyond organic” when it comes to inspecting indoor-production facilities. “We get indoor producers to look at the amount of electricity they use and reduce it,” Black says, noting that the US Department of Agriculture has never had to deal with crops grown under high-intensity discharge lights in warehouses the size of a football field.

Third-party certification services, including Certified Kind, Clean Green and the Organic Cannabis Association, seek to identify cultivators who act as caring stewards of the earth as well as safe producers of pesticide-free cannabis. John Paul Maxfield, co-founder of Colorado’s Organic Cannabis Association, says that creating a market for organically grown cannabis will happen as the industry continues to mature. “As prices become more competitive,” Maxfield muses, “differentiators become an important thing.”

With the proper third-party certification verifying their claims, growers can distinguish their products as being of the highest quality, while assuaging consumer concerns about pesticide contamination and environmental damage. Maxfield hopes that the fledgling cannabis industry will follow the evolution of the organic-food movement, first with independent certification agencies working state by state, then with federal legalization and the USDA finally establishing national standards for organically grown cannabis.

Andrew Black spent over 11 years working as a USDA organic certifier before he started Certified Kind in 2014, inspecting and approving 21 cultivators according to rigorous standards that include not only pesticide testing but social-justice considerations as well. “We don’t want to see cannabis workers getting exploited,” Black explains. Here he’s taking a far more progressive stance than the USDA, which routinely ignores substandard working conditions for the immigrants employed by meatpacking plants and huge agricultural concerns. “If we ask farmers to treat the land with care and consideration, then they should treat employees with care and consideration also,” Black says—including the right to collective bargaining and a living wage. In this way, he intends his company’s certification process to “create a mechanism to encourage growers to treat workers with respect.”

Only connoisseurs, smokers and activists who care deeply about cannabis can influence industry practices and spur them to develop in a eco-friendly direction that redefines conscious capitalism. The legacy of the underground cannabis industry involves a rejection of the environmentally destructive and unhealthy status quo and the adoption of enlightened values, including care for the earth and compassion for the people and animals that live on it. “People want to know that their cannabis is grown using organic-farming methods, and have a certifier that holds farmers to that basic standard,” Black says. “Organic agriculture means less toxic chemicals in our air, soil and water.”

So the next time you take a trip to the dispensary, ask for sun-grown or certified eco-friendly cannabis, and insist that retailers test for pesticide contamination. Cannabis is an incredibly safe, nontoxic substance, and we need to ensure that it remains pure and positive to ingest in every possible way.